The present invention relates to a new and improved reference value transmitter for a drive regulation apparatus or system, wherein the reference value transmitter is provided with a control store, in which at least permissible jerk or jolt values and threshold values of acceleration are stored and which is connected with a reference value clock pulse generator or transmitter and three integrators for the respective formation of acceleration, velocity and displacement path, and wherein upon the appearance of clock pulses generated by the reference value clock pulse generator or transmitter the output of the third one of such integrators is supplied to a displacement path regulation circuit of the drive regulation apparatus or system.
In U.S. Pat. No. 4,337,847granted July 6, 1982, a drive control has become known which is concerned with a digital reference value generator of the aforementioned type in which the control store consists of a programmable read-only memory (ROM) which is supplied with set or reference value clock pulse signals or pulses by the clock pulse generator of a digital computer by way of a frequency divider. Upon the presence of reference value clock pulse signals the associated jerk or jolt values are called up and displacement path-reference values are produced by numerical integration having regard to the acceleration limiting values. With such displacement path-reference values, which are dependent only on permissible jerk and acceleration values, it is possible, for example in the case of passenger elevators, for travel curves to be generated by means of which optimal results in relation to travelling comfort and the duration of travel can be achieved.
On the other hand there are certain limitations to the application of such reference value transmitters, according to the kind of drive under consideration. For example, the running-up or acceleration of an asynchronous electric motor in the lower range of rotational speed can be well regulated because of a higher available torque. In the upper rotational speed range, however, the torque falls appreciably with increasing speed, and the motor requires substantially more time to achieve a predetermined rotational speed. It can therefore no longer follow the reference value transmitter hereinbefore described, working as it does with a definite, constant clock pulse frequency, so that the regulation deviation becomes greater and greater, and regulation of the motor is thrown out of gear.